Kazuya Ito, 31, was kidnapped on Tuesday as he headed to carry out his daily inspection of an irrigation project being built by his employer, the Peshawar-kai non-governmental group.

The Japanese government said it had not yet confirmed Ito’s death.

But the Japanese embassy in Kabul said the Afghan authorities had informed them that he had been killed by abductors and that his body had been found, said an embassy official who refused to be named.

An official of the aid group confirmed the killing.

"Yes they (police) have found him, unfortunately dead," deputy manager Noor Zaman of the group in eastern Nangarhar province told AFP.

Ito’s Afghan driver and translator, who were also abducted but freed after several hours, saw and recognised the body, Mashouq said.

The Afghan interior ministry had announced late Tuesday that Ito was freed in a massive operation involving police and 500 villagers. But Japan later said that statement was erroneous.

The hard-line Taliban militia, behind a growing insurgency, said Tuesday its men had taken Ito and that he was killed in a fire-fight with police who were pursuing them.

Ito’s aid group was founded by Tetsu Nakamura, a Japanese doctor who has set up projects across Afghanistan and Pakistan for more than two decades and was an outspoken opponent of the 2001 US-led war that ended Taliban rule.